The big problem is that after the lockdown many shops have restocked, so their new inventory is new. So a common problem many have is amplified as they have old stock sitting for a long time without selling. Old stock is more challenging to move than new stock, so the odds are that this stock will continue sitting in your shop if you do not do something.
The first point is to identify this stock. Luckily you have an extensive system in your POS Software to help you find this old stock.
As a tip, it's best to run it into three-month, six-month and 12-month-old periods separately as each period has a story to tell.